1. Field of the Invention
This invention relates to molded coils.
2. Description of the Prior Art
It is known from U.S. Pat. No. 3,590,329 to produce an integrally molded coil. Initially a wound coil is positioned within a mold forming member. A metal central core pin is inserted into the mold after closing for forming a hollow center bore of the coil form to be molded. The mold cavity is filled with insulating plastic material for an injection molding process. The metal core is withdrawn from the molded coil after the injection cycle and the mold is opened and the finished coil removed.
When the metal core is withdrawn from the inside of the molded coil following the injection cycle and prior to removing the finished coil from the mold, the molded portion of the coil form shrinks and warps sufficiently to distort the entrapped coil winding and cause electrical variances sufficient to limit its application to low tolerance usage.